Labels may be made in various sizes and shapes, and may further fall into one of several types. One type of label, for example, is the wrap-around label, in which a leading edge of the label is initially secured with adhesive to a three dimensional object, such as a container or other product or product packaging of any shape. The label is then wrapped around the object so that the trailing edge of the label overlaps and is adhesively secured to the label itself. Another type of label is one in which both the leading and trailing edges of the label are affixed directly to the object.
The securement of labels to bottles or other containers, for example, must be of such a quality that the labels can withstand the various conditions that may be later experienced by the containers or bottles during shipping, storage, and use thereof subsequent to the product packaging or filling operation. For example, with bottles of carbonated beverages, the labels must withstand expansion of the bottles due to the carbonation of the beverage and, for example, additional expansion and contraction during shipping and storage operations in which the temperatures of the product may vary. Moreover, the labels must also be aesthetically pleasing. For example, it may be desired that the exposed edge of a label should not readily flap, become detached from the product, have exposed adhesive, or have large amounts of adhesive forming lumps underneath the label.
In some processes, adhesive is applied to labels using a wheel coater. Wheel coaters use an open reservoir for holding the adhesive. A rotating wheel receives a coating of adhesive on its outer circumference that in turn transfers the adhesive onto the label by rolling contact with the label. The labels may be supported on a vacuum drum during application of the adhesive. A container, such as a bottle, can, or other type of object moves along a conveyor and a paper or plastic label is secured to the outer surface of the container or object during a production operation. A drawback of wheel-applied adhesive is that the open reservoir is susceptible to contamination, which may affect the quality of applied labels and lower the efficiency of the machine. Wheel coaters also require precise settings to ensure adequate results of dispensed labels. These settings must be adjusted and finely tuned each time the labels are changed.
In some labeling operations, it may be desired to apply labels having different lengths and/or widths. This may require that the vacuum drum used to support the labels during adhesive application be changed to accommodate the differently sized labels. Changing vacuum drums requires shutting down the labeling line and therefore reduces throughput.
There is a need for a manner of applying adhesive to either labels or containers, or both, in which the adhesive may be applied in a non-contact fashion, but also with reduced needs for maintenance requirements and good adhesive coverage, while at the same time using a minimum amount of adhesive to secure a label to a container. There is also a need for increased control over the amount of adhesive that is applied, especially in applications where different amounts of adhesive are required for different portions of a label. There is also a need for a labeling apparatus that is capable of applying labels of various lengths and widths to containers.